Away this week

Yours truly will be away from the blog this week, makin money and all. While am away, here's something to think about.

Fake fights on Climate crisis. Alan Thorpe writes in New Scientist.

Scepticism is one thing; cynicism and conspiracy-theorising are quite another. These are the hallmarks of a recent attempt to discredit the widely accepted theory that human-made carbon dioxide emissions are causing global warming. A loose affiliation of scientists and writers is pushing the alternative idea that fluctuations in solar activity provide a better explanation for the rise and fall in the temperature of Earth's atmosphere over the past few centuries.

Their basic argument goes something like this. When the cosmic rays that constantly bombard Earth from outer space hit water vapour rising from the oceans, they cause clouds to form in the atmosphere which shield the planet from solar radiation and cause it to cool. The sun's magnetic field dampens the effect of cosmic rays, so reducing cloud cover and causing Earth to heat up. Thus an active sun makes for a warmer planet - a correlation these scientists claim is borne out by the records.

Readers in the UK may have seen the most recent incarnation of this theory in the Channel 4 television programme The Great Global Warming Swindle, broadcast last week. The programme questioned not only the mainstream of global warming science but also the integrity of the researchers involved in it. As I am the head of the major funder of climate science in the UK, the Natural Environment Research Council (NERC), such accusations of bias, lying and prejudice were bound to catch my attention.

First, let's deal with the main thesis: that the presence or absence of cosmic rays in Earth's atmosphere is a better explanation for temperature variation than the concentration of CO2 and other gases. This is not a new assertion and it is patently wrong: there is no credible evidence that cosmic rays play a significant role. The climate system is complex and it is likely that many factors affect it, cosmic rays among them. But to claim they are a major influence is disingenuous. There is far greater evidence suggesting CO2 is the major cause of warming.